Removing oil from flowing air streams



1938- 5. J. ERLING 2,125,435

REMOVING OIL FROM FLOWING AIR STREAMS Filed Sept. 17, 1956 w Sue/2 119227 fr/zr y Mira/M 5715.

Fatented Aug. 2, i938 E T ,ji.

PATENT @FIFH REMOVING OIL FROM FLOWING AIR STREAMS Application September 17, 1936, Serial No. 101,202 lln Sweden November 5, 1935 9 Claims.

In machines for creating currents of air, such air is often laden with atomized oil particles, as, for example, in air pumps that require lubrication. This oil fog is highly objectionable and is attended, incidentally, with considerable loss of oil. It is known to provide in the air passage a narrow opening comprising a slit or slot of not above about one-tenth of a millimeter or less through which the air is free to flow. It has been found that the oil particles travelling along with the air will precipitate on the outer side of the slit and may be collected in a pool or well into which the precipitated oil drains. The air is thereby freed of oil. Means illustrating such an oil 2,047,728, July 14, 1936. In practice, it is necessary, in order to insure highly efficient operation, that the width of the air slot be maintained of the value specified and also that such width be maintained practically constant independent of depositions on the surfaces adjacent the slot of contaminating solids contained in the air and the oil drops.

My invention involves the above known principle but is an improvement thereon in that it is adapted to fulfill the above requirements. It comprises a tightly wound wire spring so arranged that the air is forced to pass between the coils of the spring. The necessary range of slots may be obtained by making one end of the spring closed, either by shaping it, for instance, as a cone or by covering the opening left by the spring with a lid or the like. When the air is pressed into the cavity formed by the spring it exerts in both cases an axial pressure on the spring which separates the turns from each other, so that narrow slots or slits are formed therebetween. If the surfaces of the slots become coated, so that the width of the slots tends to be'reduced, this is automatically compensated for, because the air pressure is somewhat increased, the consequence of which is that the spring is stretched correspondingly and the efiective minute width of the slots is maintained. In this manner the width of the slots is automatically kept practically constant at a concatcher is disclosed in the patent to Erling, No.

modified forms of spring that may be substituted for the spring of Fig. 1.

The chamber l is tightly connected to the outlet of an air pump or compressor (not shown). The chamber 2 is connected to an air outlet. The construction may also represent a flow passage for air in which the passage connects at one end with a vacuum pump and at the other end with the atmosphere. The chambers I and 2 are separated from each other by a wall 3, in which is arranged an oil catcher consisting of a cylindrical helical spring 4. The end of the cavity of the spring 4 turned towards the chamber 2 is closed by a lid 5. The other end of the cavity communicates with chamber I. The spring 4 may, for instance, be soldered to a cylindrical flange 6 of a disc I which is secured to the wall 3. The lower part of chamber 2 is provided with a container in the form of a pocket 8 into which the removed oil flows and is collected. After the oil remover has stopped workingbecause the pump has been stopped-the oil contained in the pocket 8 flows through a bore 9 into the chamber I, where it is added to an oil bath l0 provided in the bottom of chamber 1 for the lubrication of the compressor.

During the operation of the arrangement the channel 9 must not, of course, be open because this would afford an unrestricted opening for flow of the air from chamber i to chamber 2. To prevent this the bore 9 is covered by a plate-spring ll which in tensionless state just covers the orifice of the bore 9 or leaves a narrow slot between the part H and the rim of the orifice.- As soon as the compressor is started, a pressure is generated in chamber I, the plate-spring H thereby being pressed against the orifice of the bore 9 and closing it, so that air cannot flow this way. After the pressure has ceased, the communication between the bore 9 and the chamber 1 is opened so that the oil, as mentioned above, can flow off to the oil bath l0.

In Fig. 2 is disclosed a conical spring l2, whose shape is such that no special means is required to provide a closed end.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. Means for removing oil particles from a stream of air flowing througha passage from a source of higher pressure to a source of lower pressure comprising a wall having an opening forming a part of said passage, a spiral spring with one open end and one closed end, the open end being secured in said opening and the spring being otherwise unsupported, said spring extending from said wall toward the region of lower pressure and beingso wound that under balanced pressure its adjacent turns aproximately touch one another and substantialiy close said passage but which, during maintenance of said differential air pressures, is adapted to be thereby expanded to afford between said turns slots of a width sunficient to allow flow of air therethrough but so narrow as to arrest and precipitate oill particles.

2; Means ior removing oil particles from a stream of air flowing through a passage from a source of higher pressure to a souice of lower pressure comprising a wall having an opening forming part of said passage, a helical spring with one open end and one closed end supported solely by having open end secured in said opening with its body and closed end extending therefrom toward the source of lower pressure, said spring being so wound that under balanced pressures its adjacent turns normally touch one another and, together with the closed end of the spring, substantially close said, passage, said spring during said flow of air as specified being adapted to be elongated by air pressure to form a long, narrow helical slot adapted to allow passage of air and adjacent to which oil particles may precipitate.

3. Improved means for eliminating'oil particles frpm air flowing through apassage from a source of'higher pressure to asource of lower pressure, said means comprising a wall having an opening forming part of said passage, said jopening being flared outward from its inlet toward its outlet, and a spiral spring secured to the wall at the contacted inlet end of said opening and extending through said opening and closed and unsupported at its outer end and being so wound that during 7 the maintenance of difierential air pressures it expands to afior-d betwen turns slots of a width sufficient to allow flow of air therethrough but so narrow as to arrest and precipitate oiiparticles.

4. Improved means for eliminating oil particles from air flowing irom a source of higher pressure to a source of lower pressure, comprising a wall having an openim forming a part'of said passage a spiral spring interposed in the opening in said, wall, said springbeing so wound and positioned that under balanced pressures its adjacent turns approximately touch one another and substan-. tially close said passage but which, during the maintenance of said difierential air pressures, is adapted to be thereby expanded to afford between said turns slotspf minute Width'allowing flowof air therethrough and adjacent to which the all particles may precipitate, a disc secured to the 7 side of said wall exposed to said higher pressure 'and having an opening aligningwith the opening in the wall,and a flange along the inner edge oi the disc to which the open ends of the spring is ell, said spring being so wound and-positioned that under balanced pressures its adjacent turns approximately touch one another and substantially close said passage but which, during the maintenance of said differential air pressures, is adapted to be thereby expanded to afford between said turns slots of minute ,width allowing flow of air therethrough and adjacent to which the oil the low pressure side of said wall adapted to receive and collect precipitated oil.

6. Improved means for eiiminating oil particles from air flowing from a source of higher pressure to a source of lower pressure, comprising a wall having an opening forming a part of said passage, a spiral spring interposed in the opening in said wall, said spring being so wound and positioned that under balanced pressures its adjacent turns approximately touch one another and substantially close said passage but which, during the maintenance of said differential air pressures, is adapted to be thereby expanded to afiord between said turns; slots of minute width allowing flow of air therethrough and adjacent to which the oil particles may precipitate, an oil pocket on the low pressure side of said wall adapted to receive and collect precipitated oil, an oil reservoir open to the high pressure side of said wall, there being an opening in said wall connecting said oil pocket and oil reservoir, and a closure for said opening adapted to be maintained in operative position under the influence of said higher pressure.

7. Improved means for eliminating oil particles irom air? flowingirom a source of higher, pressure 'jto a source of lower pressure, comprising a wall having an opening forming a part of said'passage, "a spiral spring interposed in the opening in said ,wall, said spring being so wound and positioned that under balanced pressures its adjacent turns approximately touch one another and substantially close said passage but which, during the maintenance of: said differential air pressures, is adapted to be thereby expanded to afford between said turns slots of minute width allowing flow of air therethrough and adjacent to whienthe oil particles may precipitate, an 911 pocket on the low pressure side of said wall adapted to receive and collect precipitated oil, anoil reservoir open to the high pressure side of said wall, there being an opening in aid wali connecting said oil pocket and oil reservo r, and a spring-plate positioned on the side of said wall exposed to higher presstue and movable out of and into position to close said opening and being adapted to be maintained in the latter position in sealingrelation with said opening underithe influence of said higher pressure.

8. Means for removing oil particles from a stream of ain flowing through a passage from a source of higher pressure to a source of lower pressure comprising a wall having an opening forming apart of said passage, a spiral spring with one open end and one closed end, the open 'end being secured in said opening and the spring being otherwise unsupported, said spring extending from said wall toward the region of lower pressure and being so wound that under balanced pressure its adjacent turns approximately touch one another and substantially close said passage but which, during maintenance of said diiierential air pressures, is adapted to be thereby expanded to afford between said turns slots of a width 'not exceeding a fraction of a millimeter to thereby allow flow of air therethrough but arrest and precipitate oil particles. Y

9. Means for removing oil particles from a stream of air flowing through a passage from a source of higher pressure to a source of lower pressure comprising a wall having an opening forming a part of said passage, a spiral spring with one open end and one closed end, the open end being secured in said opening and the spring particies may precipitate, and an oil pocket on being otherwise unsupported, said spring extending from said wall toward the region of lower pressure and being so wound that under balanced pressure its adjacent turns approximately touch one another and substantially close said passage but which; during maintenance of said differential air pressures, is adapted to be thereby expanded to afford between said turns slots of a width not exceeding about one-tenth of a millimeter to thereby allow flow of air therethrough but arrest and precipitate oil particles.

SVEN J OHAN ERLING. 

